Metaethics 2: Moral Realism

[rahmabell]

Thank you so much this is so clear and helpful👏👏😃

[olivergroning]

The analogy of moral 'objectivity' to mathematics is very revealing, because what people forget is that mathematics is a formal system based on axioms. Axioms are statement which are defined to be true by choice (they have no deeper truth value). E.g. chess is a formal system and the rules of chess are its axioms, all board configurations following from the axioms are objectively true. On the other hand a configuration with 2 black kings on the board is not conform with the (standard) axioms and therefore 'objectively false'. With mathematics it is the same. Sometimes the statement "2+2=4" is taken as an example for an 'objective truth', where it is not mentioned that one needs a whole machinery to make this statement 'objectively true'. And here it is (for those interested in it):

Definition of "="
Axiom 1: x=x
Axiom 2: If x=y then y=x
Axiom 3: If x=y and y=z then x=z
Axiom 4: If x belongs to M and x=y then y belongs to M
Definition of the natural numbers (N)
Axiom 5: 0 is a N
Axiom 6: If n is a N then the successor of n which is S(n) is also a N
Axiom 7: If and only if x=y then S(x)=S(y)
Axiom 8: There in no n belonging to N for which S(n)=0
Axiom 9: 1=S(0), 2=S(1), 3=S(2), 4=S(3), ... (Recursive definition of the symbols of the natural numbers)
Definition of "+"
Axiom 10: If n is a N then n+0=n
Axiom 11: If n and m are of N then n+S(m)=S(n+m)

And now the proof establishing the objective truth of the statement '2+2=4'

(QED)

Without the axioms the statement '2+2=4' is actually meaningless, even more so to call it true or false. So if someone tells me "moral realism works like mathematics", my immediate question is "So what are the moral axioms? What are the moral statements which are true by choice in order to establish the truth value of other moral claims?". I also like to mention that in mathematics there can be actual disagreement what is a good set of axiom to describe certain mathematical domain.

As a physicist and mathematician by training I am very puzzled how vague (and quite honestly weak) arguments for moral realism really are. From my point of view, moral realism (i.e. the existence of objective moral facts) can be justified when morality is viewed as a formal system, where I have a set of moral axiom (true by definition and choice). This would answer the diversity of morality across different societies, because these have different moral axioms. Otherwise, I would need an answer to the question "How is a world in which moral realism is true different from one where it is false?". This last question settles the question if a statement is scientific or not, i.e. can be decided by observation of the world. E.g. "There are invisible unicorns everywhere, which are impossible to detect by any method." This is a non scientific statement, it is impossible to establish if it is true or not. My feeling is that 'moral realism' is actually a non scientific statement very much akin to the one about invisible unicorns.

[martinbennett]

Your presentation takes more of a deontological perspective; your comparison with mathematics assumes an a priori derivation, however you gloss over a consequentialist point of view. From a consequentialist stand point (including utilitarianism) the comparison would be with science and your claim that ethics cannot be empirical would be as wrong as to claim that values of human health cannot be empirical.

As with other empirical disciplines (such as science and history), moral realism can potentially be how we assess whether past actions or events were good and beneficial or else bad and detrimental. An example could be the education of women over the last 200 years: have the changes in how modern societies approach women's education been for good or not? . There is plenty there that is readily measurable and although it might be possible to point out one or two odd disadvantages the overall balance of empirical evidence would make it easy to arrive at a clear judgement.

If the is/ought issue is problematic then it would be inconsistent to expect that ethics should tell what we ought to do. In fact this is part of the wider problem of induction; no set of empirically derived principles can have absolute certainty of the future, but they can suggest or strongly suggest likely consequences. Assessment of past events is possible, though we can in many cases also acknowledge a complexity that renders this assessment debatable, yet there will be other cases where there really is not much of a debate (e.g. opening up universities to women was really good!).